8th Chemistry Test - 1
28/07/2023
Student Name : _____________
Marks:40
Q.1. What is the plum pudding model of the atom?
A. An atom is a ball of positive charge with negative electrons embedded in it
B. An atom is a ball of negative charge with positive electrons embedded in it
C. An atom is a ball of positive charge with negative neutrons embedded in it
Q.2. Which scientist found evidence for the existence of neutrons?
A. James Chadwick
B. Niels Bohr
C. Ernest Rutherford
Q.3. What is the relative mass and charge of a neutron?
A. Mass = 1 and charge = -1
B. Mass = 0 and charge = +1
C. Mass = 1 and charge = 0
Q.4. An atom has 13 protons and 14 neutrons. What is its mass number?
A. 14
B.13
C.27
Q.5. An atom has an atomic number of 9 and a mass number of 19. What are its numbers of
protons, neutrons and electrons?
A. Protons = 10, neutrons = 19, electrons = 10
B.Protons = 9, neutrons = 10, electrons = 9
C. Protons = 19, neutrons = 10, electrons = 19
1
Q.6.
What does the stepped zig-zag line beginning under boron (B) on the periodic table show?
1. The division between gases and solids
2. The division between metal and non-metals
3. The division between elements and compounds
Q.7. Hydrogen is often shown separately on the periodic table. What type of element is it
classified as?
Neither
Non-metal
Metal
Q.8. Which element is in period 1 and group 0?
Hydrogen
Helium
Neon
2
Q.9. Elements in the same group have similar properties. Which element would have similar
properties to lithium (Li)?
Neon (Ne)
Caesium (Cs)
Beryllium (Be)
Q.10 Which element is a metal?
Chlorine (Cl)
Calcium (Ca)
Carbon (C)
Q.11. Which element is in group 1 and period 3?
Boron (B)
Sodium (Na)
Potassium (K)
Q.12 How do metal atoms form ions?
(2)
metal atoms lose electrons to form positively charged ions
................................................................................................................................................
................................................................................................................................................
...............................................................................................................................................
Q.13. What is a covalent bond?
(2)
A covalent bond is formed by the equal sharing of electrons from both participating
................................................................................................................................................
atoms. between 2 non metals
................................................................................................................................................
...............................................................................................................................................
Q.14. In a dot and cross diagram, what does each dot and cross represent?
(1)
electrons
................................................................................................................................................
15. The transferring of electrons occur in _ionic_______________ bonds.
(1)
16. In _covalent___________________ bonds a pair of valence electrons are shared.
3
(1)
1
The ‘lead’ in a pencil is made of a mixture of graphite and clay.
‘lead’
When the percentage of graphite is increased, the pencil slides across the paper more easily.
Which statement explains this observation?
2
A
Graphite has a high melting point.
B
Graphite is a form of carbon.
C
Graphite is a lubricant.
D
Graphite is a non-metal.
How many electrons are used to form covalent bonds in a molecule of methanol, CH3OH?
A
5
B
6
C
8
D
10
2
3
This question is about Group I elements and their compounds.
(a) The properties of some Group I elements are shown in the table.
element
boiling point
/ °C
atomic radius
/ pm
relative thermal
conductivity
observations when it
reacts with cold water
sodium
883
186
3.9
rapid bubbling but does
not burst into flame
potassium
759
227
rubidium
688
caesium
671
(i)
(ii)
value between
228 and 264
265
any value between
3.8 and 1.7
very rapid bubbling and
bursts into flame
1.6
1.0
Complete the table to estimate:
● the relative thermal conductivity of potassium
● the atomic radius of rubidium.
explodes
[2]
Describe the trend in the boiling points of the Group I elements.
decreases down (the Group) / increases up (the Group) / decreases from sodium to caesium
.......................................................................................................................................
[1]
(iii)
Use the information in the table to predict what you would observe when rubidium reacts
with cold water.
bursts into flame / extremely rapid bubbling / explodes
....................................................................................................................................... [1]
(b) Which one of the statements about the formation of a sodium ion from a sodium atom is
correct?
Tick one box.
A sodium atom gains an electron.
A sodium atom loses an electron.
A sodium atom loses a proton.
A sodium atom gains a proton.
[1]
3
(c) Is sodium oxide an acidic oxide or a basic oxide?
Give a reason for your answer.
....................................................................................................................................................
.............................................................................................................................................. [1]
(d) A compound of sodium has the formula C4H5Na.
Calculate the relative formula mass of C4H5Na.
Show all your working.
Use your Periodic Table to help you.
relative formula mass = .............................. [2]
(e) Complete the word equation for the reaction of sodium hydroxide with sulfuric acid.
sodium
hydroxide
+
sulfuric
acid
sodium sulphate
..............................
+
hydrogen
..............................
..............................
[2]
[Total: 10]
4
4
This question is about phosphorus and compounds of phosphorus.
(a) Phosphorus has the formula P4. Some properties of P4 are shown.
(i)
melting point / °C
45
boiling point / °C
280
electrical conductivity
non-conductor
solubility in water
insoluble
Name the type of bonding that exists between the atoms in a P4 molecule.
covalent
.......................................................................................................................................
[1]
(ii)
Explain, in terms of attractive forces between particles, why P4 has a low melting point.
forces of attraction between molecules
.............................................................................................................................................
AND
are weak / need a small amount of energy to break
....................................................................................................................................... [1]
(iii)
Explain why phosphorus is a non-conductor of electricity.
no moving or flowing or mobile charged particles or ions or electrons
.............................................................................................................................................
....................................................................................................................................... [1]
(b) Phosphorus, P4, reacts with air to produce phosphorus(V) oxide, P4O10.
(i)
Write a chemical equation for this reaction.
....................................................................................................................................... [2]
(ii)
What type of chemical reaction is this?
....................................................................................................................................... [1]
(c) Phosphorus(V) oxide, P4O10, is an acidic oxide.
Phosphorus(V) oxide, P4O10, reacts with aqueous sodium hydroxide to form a salt containing
the phosphate ion, PO43–. Water is the only other product.
Write a chemical equation for the reaction between phosphorus(V) oxide and aqueous
sodium hydroxide.
.............................................................................................................................................. [2]
5
(d) Phosphine has the formula PH3.
Complete the dot-and-cross diagram to show the electron arrangement in a molecule of
phosphine. Show outer shell electrons only.
H
H
P
H
[2]
(e) Phosphine, PH3, has a similar chemical structure to ammonia, NH3.
Ammonia acts as a base when it reacts with sulfuric acid.
(ii)
Write a chemical equation for the reaction between ammonia and sulfuric acid.
....................................................................................................................................... [2]
[Total: 12)
40
38
Sr
strontium
88
56
Ba
barium
137
88
39
37
Rb
rubidium
85
55
Cs
caesium
133
87
cerium
140
90
Th
thorium
232
lanthanum
139
89
Ac
actinium
–
231
protactinium
Pa
91
141
praseodymium
Pr
59
58
Ce
57
–
dubnium
Db
105
181
tantalum
Ta
73
93
niobium
Nb
41
51
vanadium
V
23
–
rutherfordium
Rf
104
178
hafnium
Hf
72
91
zirconium
Zr
40
48
titanium
La
lanthanoids
57–71
89
yttrium
Y
39
45
scandium
Ti
22
Cr
24
238
uranium
U
92
144
neodymium
Nd
60
–
seaborgium
Sg
106
184
tungsten
W
74
96
molybdenum
Mo
42
52
chromium
relative atomic mass
–
neptunium
Np
93
–
promethium
Pm
61
–
bohrium
Bh
107
186
rhenium
Re
75
–
technetium
Tc
43
55
manganese
Mn
25
–
plutonium
Pu
94
150
samarium
Sm
62
–
hassium
Hs
108
190
osmium
Os
76
101
ruthenium
Ru
44
56
iron
Fe
26
27
28
29
30
–
americium
Am
95
152
europium
Eu
63
–
meitnerium
Mt
109
192
–
curium
Cm
96
157
gadolinium
Gd
64
–
darmstadtium
Ds
110
195
platinum
Pt
Ir
iridium
78
106
palladium
Pd
46
59
nickel
Ni
77
103
rhodium
Rh
45
59
cobalt
Co
–
berkelium
Bk
97
159
terbium
Tb
65
–
roentgenium
Rg
111
197
gold
Au
79
108
silver
Ag
47
64
copper
Cu
–
californium
Cf
98
163
dysprosium
Dy
66
–
copernicium
Cn
112
201
mercury
Hg
80
112
cadmium
Cd
48
65
zinc
Zn
B
C
–
einsteinium
Es
99
165
holmium
Ho
67
204
thallium
Tl
81
115
–
fermium
Fm
100
167
erbium
Er
68
–
flerovium
Fl
114
207
lead
Pb
82
119
tin
Sn
In
indium
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
49
70
gallium
Ga
31
27
aluminium
Al
13
11
boron
6
–
mendelevium
Md
101
169
thulium
Tm
69
209
bismuth
Bi
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
N
7
–
nobelium
No
102
173
ytterbium
Yb
70
–
livermorium
Lv
116
–
polonium
Po
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
O
8
–
lawrencium
Lr
103
175
lutetium
Lu
71
–
astatine
At
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
F
9
–
radon
Rn
86
131
xenon
Xe
54
84
krypton
Kr
36
40
argon
Ar
18
20
neon
Ne
10
4
5
helium
VIII
1
VII
hydrogen
VI
2
V
He
IV
1
III
H
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
calcium
potassium
–
actinoids
Ca
K
Ra
20
19
radium
24
23
Fr
magnesium
sodium
francium
89–103
Mg
Na
Sc
12
11
21
9
7
name
atomic symbol
Be
beryllium
Li
lithium
atomic number
4
3
Key
II
I
Group
The Periodic Table of Elements
6